Other ETH lib

lib/AsyncWebServer_ESP32_W5500/src/libb64/cencode.c

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+/****************************************************************************************************************************
+  cencode.c - c source to a base64 encoding algorithm implementation
+
+  This is part of the libb64 project, and has been placed in the public domain.
+  For details, see http://sourceforge.net/projects/libb64
+
+  For W5500 LwIP Ethernet in ESP32 (ESP32 + W5500)
+
+  AsyncWebServer_ESP32_W5500 is a library for the LwIP Ethernet W5500 in ESP32 to run AsyncWebServer
+
+  Based on and modified from ESPAsyncWebServer (https://github.com/me-no-dev/ESPAsyncWebServer)
+  Built by Khoi Hoang https://github.com/khoih-prog/AsyncWebServer_ESP32_W5500
+  Licensed under GPLv3 license
+ *****************************************************************************************************************************/
+
+#include "cencode.h"
+
+const int CHARS_PER_LINE = 72;
+
+/////////////////////////////////////////////////
+
+void base64_init_encodestate(base64_encodestate* state_in)
+{
+  state_in->step = step_A;
+  state_in->result = 0;
+  state_in->stepcount = 0;
+}
+
+/////////////////////////////////////////////////
+
+char base64_encode_value(char value_in)
+{
+  static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+  if (value_in > 63)
+    return '=';
+
+  return encoding[(unsigned int)value_in];
+}
+
+/////////////////////////////////////////////////
+
+int base64_encode_block(const char* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in)
+{
+  const char* plainchar = plaintext_in;
+  const char* const plaintextend = plaintext_in + length_in;
+  char* codechar = code_out;
+  char result;
+  char fragment;
+
+  result = state_in->result;
+
+  switch (state_in->step)
+  {
+      while (1)
+      {
+      case step_A:
+        if (plainchar == plaintextend)
+        {
+          state_in->result = result;
+          state_in->step = step_A;
+          return codechar - code_out;
+        }
+
+        fragment = *plainchar++;
+        result = (fragment & 0x0fc) >> 2;
+        *codechar++ = base64_encode_value(result);
+        result = (fragment & 0x003) << 4;
+
+      // fall through
+
+      case step_B:
+        if (plainchar == plaintextend)
+        {
+          state_in->result = result;
+          state_in->step = step_B;
+          return codechar - code_out;
+        }
+
+        fragment = *plainchar++;
+        result |= (fragment & 0x0f0) >> 4;
+        *codechar++ = base64_encode_value(result);
+        result = (fragment & 0x00f) << 2;
+
+      // fall through
+
+      case step_C:
+        if (plainchar == plaintextend)
+        {
+          state_in->result = result;
+          state_in->step = step_C;
+          return codechar - code_out;
+        }
+
+        fragment = *plainchar++;
+        result |= (fragment & 0x0c0) >> 6;
+        *codechar++ = base64_encode_value(result);
+        result  = (fragment & 0x03f) >> 0;
+        *codechar++ = base64_encode_value(result);
+
+        ++(state_in->stepcount);
+
+        if (state_in->stepcount == CHARS_PER_LINE / 4)
+        {
+          *codechar++ = '\n';
+          state_in->stepcount = 0;
+        }
+
+        // fall through
+      }
+  }
+
+  /* control should not reach here */
+  return codechar - code_out;
+}
+
+/////////////////////////////////////////////////
+
+int base64_encode_blockend(char* code_out, base64_encodestate* state_in)
+{
+  char* codechar = code_out;
+
+  switch (state_in->step)
+  {
+    case step_B:
+      *codechar++ = base64_encode_value(state_in->result);
+      *codechar++ = '=';
+      *codechar++ = '=';
+      break;
+
+    case step_C:
+      *codechar++ = base64_encode_value(state_in->result);
+      *codechar++ = '=';
+      break;
+
+    case step_A:
+      break;
+  }
+
+  *codechar = 0x00;
+
+  return codechar - code_out;
+}
+
+/////////////////////////////////////////////////
+
+int base64_encode_chars(const char* plaintext_in, int length_in, char* code_out)
+{
+  base64_encodestate _state;
+  base64_init_encodestate(&_state);
+  int len = base64_encode_block(plaintext_in, length_in, code_out, &_state);
+
+  return len + base64_encode_blockend((code_out + len), &_state);
+}